Shall be located in any front or side yard, or within 20 feet of any rear lot line, except that freestanding heating and cooling equipment may be located in the side yard, provided that it is not located forward of the front line of the house or closer than 20 feet from the front lot line whichever is farther, and closer than five feet from the side lot line. On a corner lot, such equipment shall be allowed in a yard that abuts a street, provided that the main entrance to the premises is not in the same yard and that an adequate landscape buffer, approved by the Building Department, is installed and maintained. On a corner lot, such equipment shall not be located in the rear yard nearer the street than 1/2 of the side yard setback for the property, but in no event closer than five feet to the property line. At the time of installation of any such equipment, the property owner shall file with the Building Department proof that the equipment has a certified sound-level rating at the adjoining property line not exceeding 50 decibels. In addition, any such equipment shall be screened in a manner approved by the Building Department.